If the forward voltage drop of LED is 5V, then R324 can be omitted, and the triode can also work directly in the saturated conduction region (the magnification can be larger); If the current output of the infrared output module is 100 mA, the LED current of 0.5W is 100mA, and the LED current of 1.5W is 300mA, then the amplification factor of the transistor needs to be above 30. Because it works in the saturation region, the power consumption on the transistor is small, and the patch is enough.
CD40 17: Decimal Counter/Pulse Distributor
CD40 17 is a 5-bit Johnson counter with 10 decoded output and CP, CR and INH inputs. Clock output
cd40 17
The Schmitt trigger at the input has the function of pulse shaping, and there is no limit on the rising and falling time of the input clock pulse. When INH is low, the counter counts on the rising edge of the clock; Conversely, the counting function is invalid. When CR is high, the counter is cleared.
Johnson counter provides fast operation, 2-input decoding strobe and burr-free decoding output. Locking the door ensures the correct counting order. The decoded output is usually low level, and remains high level only during the corresponding clock cycle. The carry of the CO signal is completed once every 10 clock input cycle, which is used as the down pulse clock of the multistage counting chain.
CD40 17 provides four packaging forms: 16 lead multilayer ceramic duplexer (D), fused ceramic duplexer (J), plastic duplexer (P) and ceramic chip carrier (C).